1. Field of the Invention
The present invention is related to a liquid discharge apparatus including a plurality of heads having liquid dischargers with nozzles aligned in parallel in a row and a method for discharging liquid by using a plurality of heads having liquid dischargers with nozzles aligned in parallel in a row. More specifically, the invention relates to a technology for individually setting the trajectories of droplets for each liquid discharger and enabling each liquid discharger to discharge droplets in appropriate directions.
2. Description of the Related Art
One type of known liquid discharger is an inkjet printer. There are two types of known inkjet printers: 1) a serial printer in which a head is moved in the width direction of a recording medium while discharging droplets onto the recording medium as the recording medium moves in the feeding direction; 2) a line printer in which a line head is disposed across the width of a recording medium and only the recording medium is moved in the direction perpendicular to the width direction of the recording medium while droplets are discharged from the line head onto the recording medium (e.g., Japanese Unexamined Patent Application Publication No. 2002-36522).
When a line head is formed according to the above-mentioned known technology, the number of liquid dischargers becomes greater than those of the head of a serial printer. Therefore, for the line head, there is a problem in that the discharge characteristic of each liquid discharger varies greatly.
When the discharge characteristic of the liquid dischargers of a serial printer varies to a certain degree, dots can be overlapped to fill in space in dot rows already formed. In this way, the variation in the discharge characteristic can be minimized.
On the contrary, the head of a line printer does not move, and, therefore, once an area is recorded, it cannot be re-recorded by overlapping the dots. Thus, the line printer has a problem in that the characteristic of each liquid discharger varies in the alignment direction of the liquid dischargers, causing uneven streaks.
In other words, when the characteristic of each liquid discharger varies, this cannot be compensated for.